1. Field of the Invention
This invention relates to improved safety valves and, more particularly, to safety gate valves and related mechanisms, on the gate and on the housing, for locking of the gate in the closed position.
2. Description of the Background Art
In the field of fluid handling, it is a common practice to insert a valve between lengths of pipe so that the flow of fluids through the pipes may be selectively interrupted or continued at the control of an operator. One common type of valve is that formed with an apertured housing and a reciprocable plate or gate. Valves of such type are commonly called knife valves or gate valves. The gate is reciprocable into and out of the housing. The housing is coupled to the flanges of aligned pipes through which the conveyed fluid moves. When the gate is retracted out of the housing, the valve is open to allow the flow of fluid through the pipes and housing. When the gate is advanced into the housing, the apertures of the housing are blocked by the gate and the flow of fluid through the pipes and housing is precluded. The housing halves on opposite sides of the gate are secured on their axially exterior faces to the flanges of the pipes. Their interior faces are provided with elastomeric sleeves in tight compressive contact with the gate when closed. Movement of the gate is effected through an automatic or manual actuator thereabove.
One typical knife valve is disclosed in Clarkson U.S. Pat. No. 4,257,447. Such knife valve utilizes a shifting gate to open or close pipes to a flow of fluid. When, however, it is desired to completely and safely terminate the flow of fluid a more complex mechanical line blind must be utilized. Such blinds are disclosed in a large number of prior art patents.
Blinds are presently considered to be the most reliable method to fully shut off a flow of fluid for "man-safety" purposes. In order to shut off or blind a pipe, a complex, expensive mechanical blind fitting or device has to be manually unbolted. Thereafter, jacking screws are applied separating the flanges of the coupled pipes so the blind or blank section of the gate plate can be swiveled between the flanges. The jacking screws are then released and the fitting is bolted back to reseal the coupling. The flow of fluid has to be shut down while this procedure is being accomplished. On large lines this can take two or more mechanics one half of a day, or longer, if the piping is not accurately aligned.
As illustrated by a great number of prior commercial devices as well as patents, efforts are continuously being made in an attempt to improve valves whereby pipes may be shut down more efficiently, conveniently, reliably and economically. None of these previous efforts, however, provides the benefits attendant with the present invention. Additionally, prior valves do not suggest the present inventive combination of component elements arranged and configured as disclosed and claimed herein. The present invention achieves its intended purposes, objectives and advantage over the prior art devices through a new, useful and unobvious combination of component elements, with the use of a minimum number of functioning parts, at a reduced cost to manufacture, and by employing only readily available materials.
In order to assure ultimate convenience and safety, the present invention provides a pad lock, two simple brackets and a quick disconnect gate-stem pin so no one can accidentally operate the valve. The benefits include: (1) One operator, not a mechanic, can operate the blind valve in a matter of minutes; (2) The process does not have to be shut down; (3) The device can operate as a shut off valve during normal operations; and (4) Nothing is ever unbolted so piping misalignment is never a problem.
Therefore, it is an object of this invention to provide an improved safety gate valve comprising housing walls secured together in face to face relationship with an aperture extending through each housing wall in alignment about a central axis and defining a chamber therebetween; a gate plate reciprocable between an upper open position wherein the gate plate is oriented for allowing the flow of fluid through the apertures and the chamber and a lower closed position wherein the gate plate is oriented for precluding the flow of fluid through the apertures; annular sleeves fabricated of an elastomeric material and having sealing projections positioned in operative association with the apertures and extending into the chamber in sealing contact with the gate plate when in the closed position to form a bidirectional seal; locking means comprising a first arm laterally secured to one housing wall and a second arm laterally secured to the gate plate for movement therewith, each arm having a hole therethrough in alignment when the gate plate is in the lower closed position, and with a pad lock positionable through the holes for securing the gate plate against being raised to the upper open position when the gate plate is locked in the lower closed position; an actuator rod movable to reciprocate the gate plate between the upper open and lower closed positions; and a gate stem pin positionable through an opening at the lower end of the actuator rod and an opening at the upper edge of the gate plate whereby movement of the actuator rod will reciprocate the gate plate between the open and closed positions, the gate stem pin being removable from the openings whereby movement of the actuator rod will not reciprocate the gate plate between the open and closed positions, the gate stem pin also including a flexible connector coupling the gate stem pin with respect to the housing walls to preclude misplacing the gate stem pin.
It is a further object of the present invention to rapidly shut off the flow of fluids between pipes in a reliable, convenience and safe manner.
It is a further object of the present invention to terminate the flow of fluids in a line without shutting off the system.
Lastly, it is a further object of the present invention to simplify the blinding of pipes.
The foregoing has outlined some of the more pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more promiment features and applications of the intended invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or by modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.